Kenne Bell Twin-Screw Supercharger - Force-Fed Atmosphere

Strap a blower to your fifth-gen and let the good times really roll

The Kenne Bell 2.8-liter twin-screw supercharger is perfect to stuffing a lot more performance into an otherwise stock LS3 engine. For those want even more they also offer 3.6L and 4.2L versions.

The newest iteration of our beloved Camaro is, to be kind, on the heavy side. And the quickest way to make it feel “lighter” is to up the car’s power output. It’s all about the power-to-weight ratio, which is why a 30hp go kart can feel scary fast and a 436hp ’10 Camaro can feel, well, not fast enough. Once you have the epiphany that your Camaro needs more power, then the big question becomes, “How?” Well, one answer is forced induction. Slamming more atmosphere into your LS3, L99, or any engine, is the quickest way to boost output and ratchet up the fun factor of your Camaro.

Kenne Bell has been in the twin-screw supercharger business for over 20 years and they have a line of positive-displacement blower kits specifically designed to fit under the hood of GM’s newest generation of Camaro. Their blowers come in 2.8L, 3.6L, and ginormous 4.2L variations, with the 2.8L being perfect for an otherwise stock Camaro.

The blower is a twin-screw arrangement and has very little parasitic loss; up to 100 hp less. This, along with their larger displacement, and uber-efficient 4x6 rotor profiles means more power is generated from each pound of boost, and after all, it’s all about power. They can also churn out more boost (up to 15 pounds) before needing to move from a standard six-rib to a more expensive eight-rib belt system.

Actually, there’s more to a blower than just the power output. According to Kenne Bell, their superchargers are whisper quiet with no gear growl, and the oil dipstick is far easier to deal with than the typical sight glass. Another key to the unit’s performance is their “dual pass” intercooler and heat exchanger system. Again, cooler air equates to more power. See a theme developing here?

Superchargers such as this are termed “positive displacement” since compression happens within the blower. Instead of air being drawn in through the top like a typical Roots unit, it’s drawn in through the inlet port and pushed into the engine along the axis of the rotors. The intake is positioned on the end of the two screws, which are designed to overlap but not touch, leaving a small gap or pocket. As the screws turn, the gap gets smaller. This compresses the air as it moves along the screws up to the point where it enters the intake. The rotors, instead of having nearly straight lobes, are twisted into a steep helix shape. Thanks to a vacuum-referenced bypass valve, the inlet pressure is equalized with the manifold pressure. This pretty much negates any parasitic loss while cruising and makes for a very efficient design.

As for the kit, it retails for $6,999 and comes complete including a Boost-A-Pump fuel system, 47lb injectors, billet fuel rails, Mammoth cold-air kit, and all the fittings and hardware needed. For another 300 bucks you can upgrade the blower to the liquid cooled version, which under severe high-boost conditions, can dramatically lower the temp of the oil in the blower, up to 200 degrees.

At over 190 pages and 500-plus images, they also have one of the most detailed instruction manuals we’ve come across. This is a good thing, since while the kit isn’t hard to install, it does fall on the complicated side of the bell curve. As Jim Bell told us, “our primary goal with the standard 8-psi 2.8L Mammoth system was to offer a kit that would maximize airflow and horsepower so costly upgrades (supercharger, inlet system, MAF meter, manifolds, intercooler, etc.) were not necessary up to 1,000 hp. If you ever want more power, you simply need to buy the larger blower and bolt it on, the rest of the system is good to go.”

So, let’s take a quick look at how their system bolts under the hood of a fifth-gen Camaro.

1. Before the new stuff can start making loads of power, the stock stuff needs to vacate the area. First up is removing the stock airbox and engine cover. To say the instruction manual from Kenne Bell is “step-by-step” would be a huge understatement; it’s 190 pages with well over 500 images. So, while the install is complicated, it’s certainly doable for the average gearhead.

3/29

2. To get more room to work, the coolant was drained and the radiator and fan assembly were removed.

4/29

3. Blowers love to spin hard, which can actually cause the pressed-on crankshaft pulley to spin on the crank snout. This is bad. To remedy this, Kenne Bell provides a kit to pin them together. The first step was to install this jig. We then drilled two holes with the supplied bit and used a hammer to tap the pins into place.

5/29

4. After unhooking the fuel system and unplugging the wiring harness, we unbolted and removed the factory LS3 intake. With the intake gone, we used some tape to temporarily close off the intake ports on the heads.

6/29

5. In preparation for plumbing in the intercooler, we disconnected the heater hoses from the engine as well as where they go through the firewall.

7/29

6. The rear heater core hoses were modified using the supplied 90-degree bends. This will help them clear the blower assembly.

8/29

7. After pulling the driver-side black plastic inner wheelhouse, we removed the windshield washer reservoir tank to make room for the huge 4.5-inch intake system. Kenne Bell supplies a new washer bottle to take its place elsewhere in the engine bay.

9/29

8. Using a 10mm wrench, we removed the thermostat assembly and replaced it with a 180-degree version.

10/29

9. After removing the nose of the Camaro, we tackled installing the intercooler. The air dam was modified to allow for maximum flow and the lines were run back through to the intercooler pump (arrow).

11/29

10. Above the intercooler pump, we mounted and plumbed in the preassembled intercooler reservoir.

12/29

11. Following the detailed instructions, we then wired the intercooler pump into the Camaro’s fuse box.

13/29

12. For more blower and air intake clearance we used the supplied brackets to rotate the driver-side coil packs downward on the valve covers.

14/29

13. The increase in power pretty much maxes out or exceeds the capabilities of the stock fuel system, so Kenne Bell includes their Boost-A-Pump kit. This module increases the voltage to the factory fuel pump so it can keep up with the new demands from the engine.

15/29

14. After removing the shipping tape from the intake ports on the blower manifold, we set it in place on the LS3 and bolted it down. The intake came preassembled with the billet fuel rails and 47lb injectors ready to go. Once in place, we plumbed in the water lines for the intercooler.

16/29

15. Setting the blower in place was a two-man operation. Once down, we installed the bolts snugging them at first, and then torquing them as we confirmed that everything was in the right spot.

17/29

16. The new intake had provisions for all of the Camaro’s various vacuum and EVAP lines.

18/29

17. Using the supplied silicone and gaskets, we then installed the bypass tubes and the fuel distribution block that rides right under the blower snout. In regards to the blower, Kenne Bell developed what they call a Seal Pressure Equalizer. As Jim Bell explained, “In positive displacement (PD) superchargers, the front seals typically suffer from unrelenting variable pressures being applied to them from the inside the case. High vacuum when decelerating followed by high boost when accelerating can cause the seals to wear faster than normal, which is the case with any PD supercharger. Also, seals are typically designed to seal best against one force – either vacuum or positive pressure. They seal and wear best when the application of pressure is only one direction. We have designed a porting method to apply equal pressure on our seals from both sides, neutralizing the pressure forces so there is virtually no movement of the seal or force against them other than rotational forces. Using pressure equalization, the seals will last many times longer than the conventional method.”

19/29

18. After moving the power steering pump to the side, we could then install the driver-side billet bracket.

20/29

19. After reinstalling the power steering pump, we then bolted on the factory GM 90mm throttle body. At 600 rwhp, Kenne Bell recommends upgrading to their 110mm throttle body, where it will net you another 8 hp. At higher power levels, the bigger throttle body has a bigger gain. For example, at 755 rwhp it’s worth an additional 40 rwhp.

21/29

20. The 4.5-inch Kenne Bell Mammoth intake tube, which is good to go for up to 1,400 horsepower, was then put in place. This tube had a bung in the side to accommodate the factory MAF element and came pre-fabbed and powdercoated (can be ordered polished for few additional dollars).

22/29

21. In 49 of the states, you can install this huge, high-flowing filter. As Jim Bell told us, “The main advantage of our inlet system is it pulls true cold air from outside the engine compartment. In tests, we have seen more than a 20hp difference against competitor’s kits with hot underhood inlet systems. Our filter is mounted outside, under the front valance and bumper cover where it ingests only cool, denser outside air. There’s no hot underhood, power-robbing air going to the supercharger.”

23/29

22. And in California if you want to get a “thumbs up” from the smog police, you have to run the factory airbox.

24/29

23. We then added about two-thirds of a bottle of oil to the blower and filled the radiator and intercooler systems with coolant.

25/29

24. With the installation done, we could go ahead and put the front of the Camaro back together.

26/29

25. Using the supplied handheld tuner, we loaded the new program into the ECU. This was a nice feature since it saved the added cost of having the car tuned on a chassis dyno.

27/29

26. With that done, we went back and rechecked all of our bolts and hose clamps to make sure nothing had been missed. Total install time was about 12 hours.

28/29

29/29

27. Before the install, the bone stock ’10 SS was strapped to the dyno where it put down 377 hp and 373 lb-ft to the tires. After the install, the rear wheel numbers jumped to 615 hp and 548 lb-ft! That’s on 93-octane gas with 8 psi of boost. On E85 with 18 psi of boost, the horsepower skyrocketed to 789 rwhp! “Again, that’s with a 100-percent stock manual-trans Camaro. Even the exhaust is stock,” remarked Bell. We should also note that they chassis dyno tested with the hood closed, the way we actually drive cars.